How much gas just to run the stereo?

[SethPhillips 5,000+ posts]

holy sheet.... im gonna start tellin people I have a 3 HP audio system

I predict that this thread is gonna have some good reading by the time I get home from work tonight. Seriously though, if you lose gas mileage from anything car audio related it's gonna be the added weight.

that's what im trying to say... batt's, boxes, sub's, amps..... once you gett into a competition sized system that's allot of wight..

move wight>creating power...

 

[terra 5,000+ posts]

that's what im trying to say... batt's, boxes, sub's, amps..... once you gett into a competition sized system that's allot of wight..move wight>creating power...

ya absolutely..im more worried about the 400bs sitting in my trunk the slight extra electrical output i need from the engine..if that was the case id never run my AC or use my windows..

 

[Pootie 10+ year member]

It takes gas to make electrical power, and it takes electrical power to make audio.
So when does the audio system really start to hurt gas milage?

Cruising at 45mph might take about 20hp, and a typical decent audio system might require 1hp. That's about 5%. I guess I can live with that.

Anything wrong with my math?

So let me get this straight according to you in order to use my car stereo I would have to have the engine running.......Then why is it I can play music just off the battery when the engine is off....please enlighten me....Damn gremlins all up under my hood making my stereo play

 

[SethPhillips 5,000+ posts]

allso most of the time you ( or i do) turn my system up pretty loud is to demo it for some one ( car is sitting in parked area ) or in short commutes.. i rarely crank it while im on the highway.. if i do it's only for a few min... so i think the creating power issue is out the window... and wight is more of a gas guzzler then anything...

 

[1991Brougham 10+ year member]

I've never noticed any MPG change from higher electrical use to lower electrical use or vice versa. The biggest impact I've noticed comes from engaging the A/C compressor. Back in the 80's when I did dealer trades, I took a Corsica that got 30 MPG down to 18 MPG with the A/C being on. The poor little 3.1 V-6 just wasn't that powerful. My 1991 Cadillac Brougham with a 5.7 (350) V-8 gets 24 MPG on the highway with the A/C compressor engaged and 26-27 MPG with it off. The smaller hit is due to the engine not being taxed so heavily by the load of the compressor since it is a more powerful motor.

In conclusion, the alternator's demand upon the engine appears to be constant and fairly minimal. If you want to save gas, run the A/C as little as possible. Enjoy the music as you sweat...LOL!

Rick

 

[audioholic 5,000+ posts]

You guys can act like he's a crackpot, but he's right. The more power your alt creates, be it your stock unit working harder to fulfill the non-stock stereo demand or a H.O. alt running more amperage, the more drag it will put on the engine. This takes horsepower. Assuming you step on the peddle *slightly* more to maintain your usual speeds, you will be burning more gas.

Your horsepower to wattage ratio is correct. But you also need to consider efficiency losses. Your stereo is not 100% efficient, your alternator is not 100% efficient, and there are losses in every wire and at every joint. How much all these loses add up to is anyone's guess, but a 750 watt stereo will certainly cost you more than 1hp.

The added weight is also another factor, one that is harder to substantiate. Added weight affects gas lileage differently depending on driving conditions, and of course the actual weight of the stereo system. Lets just leave it at... it decreases gas mileage a 'little' also.

With gas prices as absurd as they are these days (I pay around 4 freakin bucks a gallon here in good ole California), this isn't such a ridiculous question. And, maybe the OP was just curious.

 

[SethPhillips 5,000+ posts]

the only places i think you NEED ac would be like florida, the sother states cali and arizona... it gets in the 100 here in utah.. but i can deal with it..

 

[audioholic 5,000+ posts]

So let me get this straight according to you in order to use my car stereo I would have to have the engine running.......Then why is it I can play music just off the battery when the engine is off....please enlighten me....Damn gremlins all up under my hood making my stereo play

Do you have any idea how your vehicle's charging system works? I really dont think you do. You appear to think the energy that comes from your batteries is made by magic.

 

[Pootie 10+ year member]

Your exactly right I thought it ran off pixey dust...it doesn't //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[tarzan1930]

So let me get this straight according to you in order to use my car stereo I would have to have the engine running.......Then why is it I can play music just off the battery when the engine is off....please enlighten me....Damn gremlins all up under my hood making my stereo play

Your car battery is setup to be charged by the engine. Sure, you can turn the engine off and run the stereo for a while from the energy that was stored in the battery, but once you start the car up, it's going have to put that energy back into the battery. And that energy comes from the gas in your tank.

 

[regal8r 5,000+ posts]

Your car battery is setup to be charged by the engine. Sure, you can turn the engine off and run the stereo for a while from the energy that was stored in the battery, but once you start the car up, it's going have to put that energy back into the battery. And that energy comes from the gas in your tank.

more specifically, the alternator //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[DjiNN 10+ year member]

nah its one big battery with millions of tiny lithium batteries inside the bigger one ..

 

[blazeplacid 10+ year member]

to an extent the OP is correct

but the loss would be very minimal and as stated before if your really into the hobby it wont make a differance.

Its not like your adding a turbo to your engine where your MPG would surely go down becasue of the probable use of the gas pedal

I didnt see any differance in MPG when I added my set up (around 1400rms) compared to when my car was stock

I know because I reset my trip meter at every fill up (OCD FTW)

 

[audioholic 5,000+ posts]

Your exactly right I thought it ran off pixey dust...it doesn't //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Okay smart guy, then explain how your previous comment makes any sense within the context of this conversation. Let me give you a hint, the energy in your battery that allows you to play your stereo with the engine off.... cost you money in gas previously by building up/maintaining the charge in said battery.
I would have been happy to politely point out your flawed logic, but you had to be all smart-*** to the OP when it is you that doesn't know what he's talking about. If you aren't 100% confident in your knowledge in the subject, Id keep the cocky attitude out of it if I were you. Better yet, just try reading, rather than actually responding.

 

[terra 5,000+ posts]

Okay smart guy, then explain how your previous comment makes any sense within the context of this conversation. Let me give you a hint, the energy in your battery that allows you to play your stereo with the engine off.... cost you money in gas previously by building up/maintaining the charge in said battery.
I would have been happy to politely point out your flawed logic, but you had to be all smart-*** to the OP when it is you that doesn't know what he's talking about. If you aren't 100% confident in your knowledge in the subject, Id keep the cocky attitude out of it if I were you. Better yet, just try reading, rather than actually responding.

oh noes...you went and pissed off the 'holic..//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif